The clinch or bloodknot is considered one of the strongest knots for securing a fishing line to a fish hook. Bloodknots are very strong and relatively easy to tie. The most difficult part of the tying operation involves the formation of about four to six twists of the fishing line before the end of the line is passed through the first twist. The knot is then pulled tight to bind it against the hook eye of the fish hook, and any excess line is trimmed from the end.
The knot tying operation can cause problems for the young or old or people with physical ailments, such as arthritis. Even non-disabled adults struggle in cold conditions or low light conditions. Stabbing injuries when tying lines to hooks are not uncommon.
WO200203926, herein incorporated in its entirety by reference, describes a device that permits the safe tying of a line to a small or medium sized fish hook. Typically, small to medium fish hooks are used in estuary fishing. The use of larger fish hooks typically used in blue-water (open water) fishing with that device is not possible. Even if that device is scaled, it only permits the use of a limited subset of hook sizes used in open water, and a plurality of devices of various sizes would be required to cover the most common range of sizes of fish hooks used in blue-water fishing. This is impractical in practical use.
Another issue with the WO200203926 device is that the round holes in FIG. 1 of that specification permit some hooks that are inserted into the device to have a certain amount of freedom of movement. When the device is scaled up, this can cause the barb of the hook to protrude from the casing and pose a puncture risk to a user or cause the eye of the hook to move about in the device making line tying more difficult. Also, the round holes need to be scaled up for strength when using larger hooks so they do not break off. Even if the round holes are scaled up, they limit the range of sizes of hooks that can be accommodated within the device.
Another difficulty is that the spring clip depicted at FIG. 10 in WO200203926 and described at the bottom of page 8 is not usable in saltwater blue-water environments for any length of time as it tends to rust. The use of rust-resistant spring materials is a relatively expensive replacement.
The device in WO200203926 has been used to tie two lines together, but this results in crimping of the line during tying that can result in weakening and ultimately failure of a line during use.
Nothing above should be read as necessarily falling within the common general knowledge.